This invention relates to an adjustable electrical outlet box which may be attached to a conventional electrical junction box to enable positioning the front of the outlet box at selectable distances from the junction box.
Because of various state and federal codes, the wiring of a building today requires the use of metal conduit for holding electrical wires, and so-called electrical junction boxes on which may be mounted a variety of electrical switches or plugs for access by the users of the building. Such conduit and junction boxes are mounted within the walls of the building, with openings provided in the walls for access to the junction boxes. These junction boxes are closed on all sides except where joined to conduits and except for the fronts of the boxes which face the openings in the walls.
It is desirable that the open front of a junction box be positioned adjacent to the surface of the wall so that when a switch or plug is mounted in the junction box, the front of the switch or plug will be substantially flush with the surface of the wall. However, because of the wide variety of types of walls in which the conduit and electrical junction boxes are installed, and because the junction boxes are typically installed before the wall surfaces are applied to studs or the like, it is difficult to estimate the proper location of the junction box to ensure that the front of the switch or plug will be flush with the wall surface. If the junction box protrudes out from the wall surface, then the switch or plug will appear unsightly, whereas if the junction box is recessed too far from the wall surface, then the switch or plug to be mounted therein may not be adequately protected from spark or other electrical hazards reaching surrounding combustible materials. Also, if the junction box is too far recessed from the wall surface, it may not even be possible to mount the switch or plug therein.
A number of adjustable electrical outlet boxes have been proposed to allow mounting a switch or plug so that it is substantially flush with a wall surface. Among these are those disclosed in U.S. Pat. Nos. 707,247, 1,875,101, 2,048,611 and 3,433,886. These arrangements all show a combination specialized junction box and slidable element for holding a switch or plug and as such require installation of the specialized junction box everywhere the device is to be used. That is, the device cannot be used with conventional junction boxes and so if the device is going to be used it must be installed at the beginning. This may result in an unnecessary expense since a conventional junction box might have been just as suitable, but such determination is often difficult before the building is constructed. Also, some of the disclosed arrangements allow for adjustment screws or other implements to protrude into the space occupied by electrical wiring which, of course, could be dangerous.